This invention relates to a method and apparatus for making electric cables, particularly hollow cables through which a very low temperature coolant may be passed during operation. The invention is in particular concerned with the feeding of a conductor support to the winding station where conductors are continuously wound about the support. The support is constituted by an axial series of ring- or sleeve-like elements on which the conductors -- which expediently have a ribbon shape -- are wound to extend about and coaxially with respect to the cable axis.
Support arrangements of the above type are known in general. It has been proposed as disclosed in German Pat. No. 2 020 735, published Oct. 26, 1972 (Auslegeschrift) to maintain the support sleeves axially spaced from one another and to hold them together by winding thereabout foils or bands to thus obtain a portable, hose-like structure. This support arrangement has the advantage that, between itself and the supported conductors of the cable no impermissible forces can appear, since the differences of the thermal coefficients of contraction, because of the free displaceability of the support sleeves in the axial direction, do not lead to impermissible relative motions of the support sleeves with respect to the conductors. For assembling the cable, it has been proposed to loosely interconnect the support sleeves with one another in the axial direction by means of rods or small wire hooks.
It is a disadvantage of the above-described arrangement that the coupling components between the support sleeve effect a very unreliable and non-uniform connection. As the thus assembled support sleeves are advanced to the first cable winding station where the first layer of bands (for example, conductor ribbons) is applied, there may easily occur changes in the axial direction or relative radial shifts of the support sleeves. For this reason, the layers of the conductors applied to the support arrangement are often irregular.